Safety device



Aug. 21, 1934. v, MCCORMICK 7 1,971,114-

SAFETY DEVICE Filed June 17, 1952 WITNESSES: I I INVENTOR I HOrO/OKM COrm/CK. 7.7. 3% I v v ATTO Y a iii Patented Aug. 21, 1934 Units stars-s SAFETY niivIoE'.

Harold V. McCormick, Winnetka, 111., assignor to Westinghouse Electric Elevator Company, 0111' cage, 111., a corporation of Illinois 7 Application June 17, 1932, Seriai No. 617,807

4 Claims. -(Gl.18'7-80) My invention relates toelevators and more particularly to an improved safety-brake device to be carried by an elevator car for gripping the guide rails and retarding the car when certain abnormal conditions occur.

It has been customary to provide elevator cars with rail gripping safety devices for retarding and stopping the car when various abnormal conditions occur such as over-speeding or rupture of the hoist cables, but the safety devices previously used have been so heavy and bulky that they have added considerably to the bulk and also to the weight and inertia of the moving system. Furthermore, such safety devices have been very complicated having a great many moving parts thereby rendering them unreliable, slow, expensive and inconvenient to reset.

It is accordingly an object of my invention to provide an elevator safety device which will have fewer moving parts than those of the prior art, and which will be simpler and lighter in its construction.

It is also an object of my invention to provide a simple light safety device which will be quick and smooth acting.

The invention itself, however, both as to its organization and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description of specific embodiments when read in connection with the accompanying drawing in which:

Figure 1 is a plan view showing my improved safety device in cooperative relation to a pair of associated guide rails with a portion broken away to more clearly show the structure of one of the jaws;

2 is a plan view of a modification comprising the preferred embodiment of my invention;

Fig. 3 is a detail view showing the connecting clevis thereof, and

Fig. i is a detail View showing one of the wedge actuators.

Referring more specifically to the drawing, my improved safety device comprises two pairs of jaws l1 and 12; the pairs being disposed, respectively, adjacent the elevator guide rails 13. The two jaws of each pair comprise a rail clamp and are mounted on a common pivot pin 14 in scissor fashion whereby their outer ends are adapted to grip the stem of the guide rail 13 when the inner ends are separated by actuator wedges 15 and 16, respectively. The pivot pins 14 are supported rigidly between heavy bars 17 which join the channel members 18 at each end. The inner ends of .the jaws may be provided with rollers 21and 22 to diminish the friction. whenthe wedges are moved into engaging relationtherewith. v 1 J In order to cushion the gripping action of the 6d jaws, one of the rollers 22 of each pair-of jaws is journalled in the end of a lever 23 which is pivotally mounted on the jaw 12. A, biasing spring 24. continually reacting between vthejaw 12 and the, outer end of the lever 23 tends to es rotate the latter toward the jaw. 7

The actuator wedges 1'5 and 16 are both disposed with their thin ends extending in the same direction and are mounted on the opposite ends of a single bar 26 which extends slidably through (to a pair of cross members 27 and 28 between the channel members. The normal position of the bar 26 is such that the thin portion of each wedge is between the rollers of an adjacent pair of jaws. To actuate the jaws to rail gripping position the bar 26 is moved axially to the left thereby forcing each pair of rollers 21 and 22 apart as the thick portion of the adjacent wedge enters therebetween. The applied braking pressure is limited by the yielding of the biasing spring 24 no on each pair of jaws thereby ensuring a smooth action since the jaws will yield quickly with very little inertia and will not score the rails.

A rope lever 31 is pivoted at one end to one of the cross members 27 and at the other end is 35 connected to a rope 32 which passes around a suitable idling pulley 33 to be secured to a governor cable in the usual manner. A link member 34is pivotally connected between the wedge 16 and an intermediate point on the rope lever an 31 whereby a movement of the latter by the rope 32 will be transmitted to the wedge bar 26 with a reduction of amplitude and a corresponding increase of force. Biasing springs 35 react between the inner end of each jaw and the adjacent .35 channel member 18 to normally hold the jaws open.

In Fig. 2 I have shown a preferred embodiment wherein a ropelever 41 is journalled on the side of one of the channel members 18 with a disk 100 segment 42 which is rotated thereby. Pivotally connected to the disk segment 42 is a pair of link members 43 which are connected to the wedge actuator 16 or the wedge bar 44. As shown in Fig. 3, the link members may comprise uni- 105 tary clevis 442. As the disk segment 42 is rotated by the rope lever 41, the clevis or link members 43 transmit a motion of translation to the wedge bar 44 which will move the wedges between the rollers as above set forth. In this modification, .110

the wedge bar is not slidably supported by cross pieces but is instead supported by the engagement of the wedges between the jaws which are provided with guard members for this purpose. The wedge actuators of either safety device are so shaped that the separation of the rollers is at first very rapid and then continues slowly to apply an increasing pressure. For this purpose a shoulder 51 is provided on the wedge between the thin portion and the thick portion thereof. As shown in Fig. 4 the shoulder 51 is preferably provided near the thin end of the wedge so it will engage and separate the rollers rapidly during the first movement of the wedge. For resetting the safety device, teeth 53 are provided on the periphery of the disk 42, as shown in Fig. 2, and a toothed pinion 54 is journalied in cooperative relation thereto; After anapplication of the safety it is only necessary to give the pinion a few turns with a 'wrench to restore the device to its normal position.

It will be seen that I have provided an improved elevator safety braking device which is quick acting, simple, light, compact, and conven iently re's'ettable.

" Although I have shown and described certain specific embodiments of my invention, I am fully I claim as my invention:

1. A safety-braking device for elevators comprising two pairs of pivoted rail gripping jaws, a wedge actuator for each pair of jaws, and means for supporting and moving said wedge actuators with their thin ends extending in the same direction to operate the rail gripping jaws.

2;. A safety-device for elevators comprising two pairs of pivotally mounted rail gripping jaws, a wedge for actuating each pair of jaws to rail gripping position, a bar for supporting said wedges with their thin ends in the same direction, and rope actuated means for imparting a motion of translation to said bar.

3. An elevator safety-braking device comprising two pairs of rail gripping clamps, cams for moving said clamps to rail gripping position and a lever'me'chanism for effecting the pushing of one cam and the pulling of the other into operative engagement with the rail clamps.

4. A safety-braking device for elevators comprising two pairs of-rail gripping jaws provided with actuating arms, a slidable bar, a wedge actuator affixed to each end of the bar with their thin ends extending in the same direction and in cooperative relation to the actuating arms of the gripping jaws, and means for slidably moving said bar and wedge actuators to operate the gripping iaws.

HAROLD V. MeCORMICK; 

